python入门学习(五 字符串string和变量variable) 1.字符串 一串字符显示或者打印出来文字信息 双引号,单引号,三引号 双引号:解析功能 单引号:无 三引号:保存文本格式 Format方法 age = 3name="jason"print("{0} was {1} years old".format(name, age))print(name +"was"+ str(age) +"years old") 2....
eval:让字串变成与之对应的变量名 >>> str = 'good' >>> good = 'hello!world' >>> eval(str) 'hello!world' >>> good 'hello!world'
t = string.Template(""" Variable : $var Escape : $$ Variable in text: ${var}iable """) print('TEMPLATE:', t.substitute(values)) s = """ Variable : %(var)s Escape : %% Variable in text: %(var)siable """ print('INTERPOLATION:', s % values) S = """ Variable : {var}...
ExampleGet your own Python Server Merge variable a with variable b into variable c: a = "Hello"b = "World"c = a + b print(c) Try it Yourself » Example To add a space between them, add a " ": a = "Hello"b = "World"c = a + " " + b print(c) Try it Yourself ...
In this tutorial, you’ve learned how to replace strings in Python. Along the way, you’ve gone from using the basic Python.replace()string method to using callbacks withre.sub()for absolute control. You’ve also explored some regex patterns and deconstructed them into a better architecture ...
python3 string_template.py TEMPLATE:Variable: foo Escape: $Variablein text: fooiableINTERPOLATION:Variable: fooEscape: %Variablein text: fooiableFORMAT:Variable: fooEscape: {}Variablein text: fooiable 模板与标准字符串拼接的重要区别是模板不考虑参数类型。模板中值会转换为字符串且没有提供格式化选项。例...
Type hints is a feature to specify the type of a variable, which is useful for write correct codes. In all lab assignments, you arerequiredto write Python 3 code with type hints feature. Recall that you are required to useat leastPython 3.10, otherwise you might suffer from issues brings...
You can also format a value directly without keeping it in a variable: Example Display the value95with 2 decimals: txt = f"The price is {95:.2f} dollars" print(txt) Try it Yourself » Perform Operations in F-Strings You can perform Python operations inside the placeholders. ...
Python Of course, if we used a variable name in an expression that is not in the namespace, we will get an error. Also note, we can use formatted string literals with: Single quotesf'expression', Double quotesf"{expression}", or ...
File "/usr/local/lib/python3.4/string.py", line 95, in _invalid (lineno, colno)) ValueError: Invalid placeholder in string: line 1, col 27 >>> s = Template("hello, I am ${first_name}.${last_name}") # 更换为合法的变量名后, 正常 ...